SOCKET PRESSURE AS A FUNCTION OF PRESSURE TRANSDUCER PROTRUSION a Francis A. Appoldt, B. Aero E. Research Scientist

Local pressure, developed between the socket of a prosthetic device and the accompanying body segment, reflects such matters as comfort, stability, and proprioceptive sense . Recent interest in these areas has led to the development of a number of devices to measure pressure . Most such devices, intended for clinical use (temporary mounting in the finished prosthesis) , necessarily protrude from the inner wall of the socket, resulting in the physical displacement of flesh . The best of recent models of such devices are roughly the diameter of a pencil and the thickness of a nickel (the coin) . Our concern is with the influence of the sensor protrusion from the socket wall into the flesh on the results obtained, i .e ., to what extent the pressure readings, presumably reflecting stump-socket values, are altered by the presence of a protruding clinical-type pressure transducer. An associated issue is the following: The sockets of amputees whose femurs are inadequately padded laterodistally are usually relieved in this region. If the relief is not properly faired into the adjacent wall, local irregularities are produced. It would be of interest to determine to what extent such irregularities alter local pressure. These issues have been studied experimentally employing four subjects, all vigorous above-knee amputees, equipped with quadrilateral, to-